Judy wrote:
> This container I have here of (Pure Planet Brand) Carob-Mint
> spirulina says one serving (20 tabs) contains 9.9 mcg (or
> 495% of the USRDA) of B-12.
> Do you know anything about this?

Studies have shown that as much as 94% of the B12 in spirulina is
analogs and not usuable, which can actually increase your chances of
true B12 defeciancy by competing with the real B12.

Herbert V, Drivas G.  SPirulina and vitamin B12.  JAMA 1982; 248:
3096-3097.

Dagnelie PC, et al. Vitamin B12 from algae aappears not to be
bioavailable.  Am J Clin Nutr.  1991;53:695-697.

Carmel R. et al.  Neurological abnormalities in cobalamin deficiency are
associated with higher cobalamin analogue values then hematological
abnormalities.  J Lab Clin Med.  1989;3:57-62.